A 44 year-old woman presented with 10 days of acute onset decreased vision. She reported “floaters” and bright flashes in her eyes, left worse than right. Her eyes felt “tired,” but not painful and she had no headache. A retinal specialist found bilateral optic nerve and macular edema, worse in her left eye. She denied headache, fever, chills or meningeal symptoms. Medical history was significant for rheumatologic disease treated with sulfasalazine x years prior, though specific diagnosis was unclear, She lived on a farm with cows, chickens, ducks, guineas, cats, dogs and horses but denied any scratches or bites.
Physical exam was unremarkable aside for significantly decreased visual acuity in left eye. Fundoscopy showed bilateral optic nerve edema. There was no lymphadenopathy.
MRI brain with contrast was normal. CSF analysis was normal. ANA, DS-DNA, RF, lyme and RMSF serologies, HIV, and RPR were negative. Bartonella IgM was positive at >1:20 and IgG positive at > 1:1024.
She was treated with doxycycline and rifampin with improvement in her vision. Repeat Bartonella IgM 1 month later was negative while IgG remained elevated, confirming a diagnosis of bartonella neuroretintis.
Discussion:
The general internist should be aware of the full spectrum of Bartonella infection, called cat scratch disease (CSD). CSD usually presents with painful lymphadenopathy. Most patients with CSD report a scratch or bite from a cat, the natural reservoir for Bartonella henselae. As our case demonstrates, however, a scratch or bite is not necessary for disease transmission, which may be attributable to fleas living on the cats. Several lines of evidence support the horizontal transmission of CSD between cats and humans via the flea Ctenocephalides felis.4,5
Bartonella neuroretinitis is a rare complication of CSD, occurring in 1-2% of cases. In patients with neuroretinitis, the lymphadenopathy typical of CSD is often not present.1 Patients may present with fever and malaise, though they may have no systemic symptoms. Typical visual complaints include unilateral blurred vision. Fundoscopic exam usually reveals optic nerve edema and subretinal edema.2 Some patients develop a macular “star” on fundoscopic exam. However, this may not appear for 1-2 weeks,if at all.3 Bartonella neuroretinitis is typically self-limited. Patient with severe visual deficits are treated with doxycline/erythromycin with or without rifampin. The long-term prognosis is excellent.2
Conclusions: CSD can present in a variety of ways and the general internist should have a good knowledge of the potential manifestations of CSD to facilitate prompt and accurate diagnosis.